Method of drying liquids and the like



P. MULLER. METHOD OF DRYING LIQUIDS AND THE LIKE. APPLICATION FILED AUG-Z6, I9I3- RENEWED MAY 28,1920. 1,364,403.

Patented J an. 4, 1921.

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M N m a WIT/VESSES.

UNITED STATESTPATENT orrics.

PHILIP? Mfi'LLER, 0F VILBEL, NEAR FRANKFORT-ON -THE-MAIN, GERMAN Y.

METHOD OF DRYING LIQUIDS AND TEE LIKE.

Specification of Letters Patent.

' Application filed August 26, 1913, Serial No. 786.773. Renewed May 28, 1920. Serial No. 385,306.

employment of the high temperatures hitherto required, by exposing the finely divided particles of the substance dealt with to a drying agent (for example air) while in movement, in such manner that each minute particle of the substance is individually bathed by the stream of such agent. and is; thereby instantaneously transformed into a dry and very finely divided condition.

The operation takes place in a chamber or passage adapted to enable the substance under treatment to be taken up in a finely sprayed condition in such manner that the stream of finely divided material forms a fiat layer of mist which is projected between two layers of drying agent occupying almost the width of the drying chamber and moving closely above and beneath and parallel to the said layer and in the same direction. so that the individual fine particles never come in contact with a solid surface, or with one an other and are able therefore to traverse with out hindrance the path along which they are projected. In this way, during the whole of the drying operation properly so called,

the particles remain in free suspension in the finest condition surrounded by the drying agent, to which therefore they part with their moisture easily and rapidly.

The drying agent itself (for instance air) which is passed continuously through the chamber, may (especially in the case of substances which require delicacy in drying and especially in handling) be sterilized. filtered, freed from moisture, warmed. cooled, and if necessary ozonized or the like: hence the drying process may be combined with other methods of influencing the substances under treatment.

The dried particles sink down slowly, and are removed from the chamber by suitable means, such for example as a belt conveyer.

Experiments have shown that. in this way, it is possible to transform milk, for instance, 'at a temperature of about 40 degrees C. instantaneously into'a stable and perfectly soluble powder. The drying operat-ion may thus be effected at an unusually low temperature and -in a much-simpler, quicker and cheaper, manner than has been possible with the methods hitherto known.

Patented Jan. 4, 1921.

In the accompanying drawings, which illustrate several typical forms of apparatus for carrying out the invention, corresponding parts are marked with the same reference numerals.

Figure 1 shows a central longitudinal section of one form of the apparatus.

Fig; 2 shows a similar section of a modified .form of the apparatus.

Fig. 3 shows a similar section, partly in elevation, of another form.

Fig. 4 is a fragmentary front View of the wall down which the liquid trickles.

Fig. 5 is a like view of a modified form of the aperture through which the pressure medium passes to atomize the liquid.

Fig. 6 is a fragmentary, partly sectional view of a modified form of air and milk supply and spraying devices.

i 7 to 9 show still other modifications. lln ig. 1, which shows a central longitudi nal section of one form of apparatus, 1 is the closed drying chamber: [is the receptacle for the liquid which is to be dried in the chamber 1; 3 is a. iiozzle to which the liquid is supplied through a pipe 4 controlled by a tap 5; while 6 is 'a pipe through which a suitable atomizing medium, compressed air for example, is supplied to the nozzle 3. 7 represent feed-pipes for the drying agent (air or the like), these feedpipes being provided with nozzles which converge toward the atomized current of liquid issuing from the nozzle 3. 8 is a belt conveyer. carried over rollers 9, for removing the dried particles of liquid from the drying chamber 1. 10 is a scraper for re moving ,the dried particles of liquid from the belt conveyer 8. and 11 is areceptacle for collecting the dried particles of liquid removed by the scraper 10. 12 are exhaust fines for withdrawing the drying agent laden with moisture.

follows: The

The device operates as liquid. supplied in regulated quantity from apparatus shown invFig. 2, the drying chamber 1s again indicated by 1. In the center of this chamber is mounted a-mechanically operated rotary atomizer 13, consisting of an atomizing plate which is driven, through the medium of a shaft 14, by means, for instance, of a direct-coupled turbine 15. The operation is as follows: The liquid to be dried is introduced into ,the atomizing plate 13 from the vessel 2 through the pipe 4 under the control of a tap 5, and by the rapid rota-- tion of the plate-is dispersed through thechamberas a fine mist. The drying agent is preferably blown concentrically against, the plane of the atomized liquid, from they drying-agent feed pipes 7 situated above and beneath said plane. ,The conveyer 8, ar-

ranged underneath the atomizing plate, consists of a collecting plate driven by the turbine 15, from which plate the dried particles of liquid are conducted by a scraper 10 into 1tJhe receptacle 11 outside the drying cham- A modified construction of the drying apparatus is shown in Fig. 3. F igs.-4 to 8show details of this construction.

In this form of apparatus, 16 is a wall down which the liquid is allowed to trickle, said wall, which is preferably arrangedin a known manner as an attemperator, communicating at the top with the vessel 17 or other feed device which contains the supply of liquid. The wall 16 is preferably corrugated on the surface, but may be smooth and arranged to slope at any desired angle, or may even be vertical. Behind-this wall is provided a pipe 18 having a series of fine perforations 19 (Figs. 3, 7 and 8) or a slit 20 (Fig. 5). The pipe '18 may also be mounted separately behind the wall, in which case its openings correspond withopenings 21 (Fig. 4) in the Wall 16. Opposite the openings is a slit 22 (Figs. 3, 6 and 9) arranged in the.

upper part of the drying chamber -1.

7 When air orother pressure-medium issues, under suitable pressure, from the openings 21 in the wall 16, the liquid trickling down the wall is acted upon by the current of pressure-medium and is forced, in the form of a thin stratum of fine mist, through the slit 22 into the drying chamber 1. Any of the liquid which has escaped the action of the current, is collected in a receptacle 23 (Fig. 3) placed underneath, and from this receptacle is returned, if necessary, to the vessel 17.

The feed pipe 18 for the air or pressureled from the pipe 2 tions of the wall'16 and receives the pres- 1 sure-medium from the feed pipe 25.

The wall 16 may be detached from the pipe 18, and the liquid is led by means of a I guide-plate 26 (Fig. 7) directly on to the issuing pressure-medium. The space between the guide-plate and the pressure-medium pipe may be insulated, attemperated', or ventilated. Also, as shown in Fig. 8,-the liquid can be allowed to drop freely' on to the current of pressure-medium.

Again, as shown in the modification of the apparatus according to Fig. 9, the wall -16 may also consist of two sheet metal walls arranged parallel and close together. These walls may also be corrugated, and preferably form a closed pipe 27 or chest at their lower end. In this case the pipe 27 is provided, at the side facing of the drying chamber 1, with a series of perforations 28 opposite to which a corresponding number of nozzles, leading from the common pressuremedium vessel, debouch into the pipe. The surplus liquid and pressure-medium may be ends thereof.

In this modification, the liquid is supplied to the atomizing point by being allowed to flow down between the two Walls (which through the two lateral maybe arrangfid externally to serve as hcaters or coolers), and by being encountered in the pipe 27 by the pressure-medium and expelled through the perforations 22. I

In this modification .the feeding of the liquid may also be effected in the manner illustrated in Fig. 8. s

The liquid which is to be atomized may be treated or influenced beforehand in any desired way; for instance, it may be sterile.

ized, or enriched with any desired substances. Moreover, the pressure-medium current whichefi'ects the atomization, may

efiect the cooling or warming of'the liquid to be conveyed oratomized. The air current itself, which, as already mentioned, may be replaced by another pressure medium, may be cooled, warmed, purified, dried, moistened, or saturated with cial effects. may .be effected by the ultra-violet rays- For this purpose a source of light 29 (Fig. 3), emitting ultra-violet rays, may be mounted for examplefin frontof the wall 16 and above the delivery openings, the rays acting not merely on the finely atomized and aerated liquid, but alsoon the liquid which is still trickling down the wall, so that a thoroughly germ-free product is obtained.

An interchange of different liquids under I treatment may be effected" by placing the wall, down which the liquid flows, in comany desired I substances for the purposeof producing spe- Thus, the sterilizing of milk munication with difi'erentfee'd and storage vessels, and allowing the one or the other li uid to flow down the wall as desired.

Vhat I claim, and desire to secure by Letters Patent, is-

1. The method of drying liquids and the like which comprises finely subdividing said substance to be dried and propelling it in a fiat lamina across a drying chamber and bringing into contact with the top and bot tom surfaces of said lamina, after the latter has been formed, layers of a drying medium which are themselves propelled in the same direction as the lamina but independently thereof, the contact of the lamina and the drying layers being maintained until theparticles of the substance are measurably dried.

and propelthe particles thereof in parallel lines across a drying chamber in the form of a thin layer and, aftersaid layer has been formed, in, directing a layer of drying medium against each side of said layer-and causing said layer of drying medium to move parallel with the layer of particles, until said particles are measurably dried.

In testimony whereof I aflix my signature 30 in presence of two witnesses. I

, PHILIPP MULLER.

' Witnesses: I

RUDOLPH Fmomn, N. R. SNYDER. 

